Wire drawing machines are typically used to unwind wire from a coil of wire, draw the wire through a drawbox for reducing the diameter of the wire, and for supplying the reduced diameter wire to a downstream production machine. Machines of this type are well known, and are described, for example, in U.S. Pat. Nos. 4,099,403, and 5,097,688, both assigned to the present assignee, and expressly incorporated by reference herein.
In such a wire drawing machine, the wire is initially provided in a wound coil which is supported on some sort of rotatable turntable. Wire from the coil is then manually threaded, or passed through a drawbox or die and is wrapped several times around a power-driven drum or capstan. When the capstan is rotated, it pulls wire through the drawbox so as to reduce the diameter of the wire, and the reduced diameter wire winds onto the capstan. While having a number of wraps remain on the capstan for drawing purposes, the wire is unwound and fed to the aforementioned downstream production station. As the wire is pulled by the capstan, the turntable rotates in order to allow the wire to unwind from the coil and to proceed to the drawbox.
With all currently known and used drawing machines, the process of setting up the machine, by threading the wire from the coil through the drawbox, and wrapping the wire around the capstan a sufficient number of times, is performed manually. More specifically, an operator needs to physically present the pointed end of the wire from the coil to the drawbox, and attach the end of the wire to some sort of attachment device provided on the capstan. The attachment device can be provided in the form of a manual gripper chain which holds the wire under tension, and which allows the wire to be released when not under tension, or can be provided in the form of a set screw or wedging device. The actual type of attachment device is typically dictated by the diameter of the wire being pulled. In any event, the process is completely manual wherein the operator needs to physically present the pointed end of the wire to the drawbox and physically attach the wire to the capstan. The operator then needs to jog the capstan forward to wrap the wire about the capstan a number of times sufficient to allow the wire to be pulled by the capstan from the coil as it rotates. Currently, the individual operator has great autonomy in determining the number of wraps provided on the capstan which can lead to an acceptable wrap, but which also can damage the capstan or wire drawing machine if performed improperly. In addition, time is required for the operator to jog the capstan forward sufficiently and accurately.
Once the capstan has the appropriate number of wraps, the capstan must be stopped, and the operator again must manually remove the end of the wire from the attachment device to free it from the capstan and allow it to be fed to a downstream production machine. Once the end of the wire is released from the capstan, the operator must jog the capstan forward again a sufficient amount to allow the wire to be trained around a compensation arm and be connected to the downstream production machine. The process is a time-intensive one which is economically detrimental to the operation in that any time devoted to the initialization or set-up of such a wire drawing machine, translates into downtime for the downstream production machine.
In addition to the time requirements of current machines and systems, the manual labor component also results in a potentially hazardous work environment. Since the operator needs to manually thread the wire through the drawbox and attach and release the end of the wire to the capstan at appropriate times, the operator's hands and clothing can potentially be caught in multiple pinch points provided on the machine. In addition, it is important to understand that the wire being drawn is quite often very large diameter wire with the entire coil weighing thousands of pounds. This not only compounds the hazardous nature of current systems, but also makes the process of manually threading and wrapping the wire a grueling and exhaustive one.